Located in Chiang Saen old town, was built by King Saen Phu, the 3rd ruler of the Lanna kingdom in early 13th Century. Ancient sites include the bell-shaped, Lanna-style principal Chedi which measures 88 metres height with a base 24 metres width, is the largest structure in Chiang Saen. There are also remains of ancient Viharn and Chedi.